Jane,
when I was there in September 1981 ( our honeymoon), we only had some showers scattered in
a sunny week. That's eons ago, but don't lose your hope, as although weather is now more
impredictable than it was 20 years ago, even in the heart of summer ( as seen with the August
2002 floods ), September or June can be better than July or August.
I don't know much about Belgian canals, but I can assure you that doing a very short trip
by public boat on the canal linking Brugge to Damme on a Sunday morning is one of my dearest
memories of all european travelling:on the shores, plenty of sunday painters and picknicking
families just like in a Renoir masterpiece; and in the distance, mighty clouds over gogeous,
lush countryside. Unforgettable. I think I'm the only people in Italy that chose to spend
his honeymoon in Belgium ( as a matter of fact due to lack of financial resources for a more
appealling trip), but I didn' t regret that choice.